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HOUDIJK, H., J. J. DE KONING, G. DE GROOT, M. F. BOBBERT, and G. J. VAN INGEN SCHENAU. Push-off mechanics in speed skating with conventional skates and klapskates. Med. Sci. Sports Exerc.,Vol. 32, No. 3, pp. 635‐ 641, 2000. Purpose: Personal and world records in speed skating improved tremendously after the introduction of the klapskate, which allows the foot to plantar flex at the end of the push-off while the full blade continues to glide on the ice. The purpose of this study was to gain insight into the differences in skating technique with conventional versus klapskates and to unveil the source of power enhancement using klapskates. Methods: Ten elite speed skaters skated four 400-m laps at maximal effort with both conventional and klapskates. On the straight high-speed film, push-off force and EMG data were collected. An inverse dynamics analysis was performed in the moving reference plane through hip, knee, and ankle. Results: Skating velocity increased 5% as a result of an increase in mean power output of 25 W when klapskates were used instead of conventional skates. The increase in mean power output was achieved through an 11-J increase in work per stroke and an increase in stroke frequency from 1.30 to 1.36 strokeszs 21 . The difference in work per stroke occurs during the final 50 ms of the push-off. This is the result of the ineffective way in which push-off forces are generated with conventional skates when the foot rotates about the long front end of the blade. No differences in muscle coordination were observed from EMG. Conclusion: A hinge under the ball of the foot enhances the effectiveness of plantar flexion during the final 50 ms of the push off with klapskates and increases

Proefschrift dat onder andere een tweejarig interventie-onderzoek beschrijft naar het effect van een bewegingsprogramma bij personen met type 2 diabetes.

For most elite athletes winning an Olympic gold medal is the ultimatedream. To make this dream come true, in the first place one needs sufficienttalent. However next to this talent, several years of training with largeamounts of strenuous work is necessary. It is therefore not remarkable thatthe time required for adequate recovery may easily be compromised.Doing so, an athlete is often challenging the optimal balance betweenexercise and recovery.The general purpose of this study was to get more understanding in thephysiological adaptation processes of highly trained elite enduranceathletes during periods of strenuous training.This thesis is divided into three parts. The first part (chapter 2, 3 and 4)describes the results of a three-year longitudinal study in professionalOlympic distance (OD) triathletes in preparation for Sydney 2000 Olympicgames. Chapter 2 gives a description of some measured performancerelated physiological- and anthropometric variables in OD triathletesduring the different phases of a year. Despite a clear difference in theamount of training between the several phases during the year, nosignificant differences were found between the measured performancerelated variables during submaximal and maximal exercise intensities.In spite of large amounts of training elite OD triathletes have still a lowermaximal oxygen uptake (VO2max) compared to elite distance runners andelite cyclists. Chapter 3 describes the changes in the hematological bloodprofile, as a result of endurance- and altitude training. As red blood cellsplay an important role in the transport of oxygen to the working muscles,it is important to get insight into the dynamics of the red blood profileand its possible changes in athletes, for instance with very intensivetraining and altitude training. Over a three-year period, in a group of elitemale and female OD triathletes' blood samples were collected duringseveral moments throughout the year. It was found that intensiveendurance training had not much influence on the red blood cell profile inmale and female OD triathletes. However, it was found that most of theathletes examined (female even more than male athletes), hadhematological values (particularly hemoglobin and ferritin) close to or insome cases below the lower limit of the normal range. Altitude trainingdid alter the red blood profile significantly only when altitude training wasperformed above 2000 meters above sea level. In chapter 4, the effects ofendurance training on the endocrine system throughout a year in ODtriathletes are described. Changes in hormonal plasma values are oftenmentioned as good indicators for the balance between training andrecovery. Despite the significant differences in the amount of trainingbetween the different phases of a competitive season, no significantchanges were found in the measured hormones throughout the year inelite male and female triathletes.In the second part (chapter 5 and 6) some exercise protocols that aregenerally used to evaluate training and performance are addressed. Inchapter 5 (cycling) and chapter 6 (running), the effect of stage durationon physiological variables in an incremental exercise test was studied.For measuring reliable lactate values during an incremental cyclingexercise tests a stage duration of at least 5 minutes has to be taken intoaccount. In a running protocol, the stage duration for obtaining bloodlactate values that match exercise intensity, should be at least 6 minutes.When measuring maximal values such as peak VO2, peak heart rates ormaximal workload incremental protocols with increments every minuteare sufficient.In the third part (chapter 7 to 9) training intervention studies are described.The purpose of these studies was to get more insight into the physiologicalchanges of the human body during periods of imbalance between trainingload and recovery. Chapter 7 describes the effects of a 50% reduction intraining load over a period of 21 days on some performance-relatedvariables. Many trainers and athletes are afraid to reduce the training asthey think this will cause a loss in performance. However, the resultsdescribed in this chapter show that this fear is not supported by evidence.Furthermore, it was found that an intermittent training program had nobenefit above a long slow distance training program. In chapter 8, theresults of a training intervention study (overreaching) are described.The main purpose of this study was to investigate whether the generallyaccepted overtraining markers are useful, and can be used as early markersfor overreaching. The main outcome of this study was that simple psychologicalquestionnaires appear to be a more indicative and sensitive markersfor detecting overreaching/overtraining in an early stage compared to themeasured biochemical- endocrinological- and physiological variables.Furthermore, it was found that overreaching is associated with earlychanges in cognitive performance, which can be detected by simplecognitive performance tests. In chapter 9, possible differences in bloodchemical, neuro-endocrine and psychological parameters in response to anintensified training period in runners and cyclists were investigated. Theresults of this study indicate that runners experienced a period ofstrenuous training as heavier compared to the cyclists. This difference ofsubjective feeling was not reflected in the measured blood chemical andneuro-endocrine variables.In conclusion, the most important findings in this thesis are:'' OD triathletes show hardly any variation in generally in sport measuredbiochemical-, hormonal-, or performance related variables.'' Regular control of the red blood profile is useful in well-trained enduranceathletes as many of these athletes have blood values close to or below thelower limit of the normal range'' The results of this study indicate that there exists an 'altitude threshold'above which hematological alterations occur.'' The endocrine system is (with the exception of cortisol) not a good toolto prevent overtraining.'' Cognitive performance tests appear to be useful to detect overreaching inits earliest stage.'' Endurance athletes are able to maintain their performance level for someweeks in spite of reducing the training volume.'' The subjective perception of very intense training is different betweencyclist and runners'' To ensure a reliable lactate level in incremental exercise tests, a stageduration of at least 5 minutes is required.

PurposeLiterature detailing the effectiveness of school-based physical activity promotion interventions in prevocational adolescents was reviewed to identify effective intervention characteristics.MethodsThe search strategy assessed studies against inclusion criteria study design, study population, school setting, language, and construct. The risk of bias of the included studies was assessed, and extractions were made of the physical activity (PA) level outcome measures and intervention characteristics regarding organizational, social, and content features. A meta-analysis was conducted to determine the overall effect of the interventions on the PA level. Identification of effective intervention characteristics was done by subgroup analyses. Meta-regression analysis was performed with PA level as dependent variable and intervention characteristics as covariates.ResultsA total of 40 eligible studies was included for meta-analyses. Among the included studies, the overall intervention effect on increasing the PA level of prevocational adolescents was weak (standardized mean difference [SMD] .19, 95% confidence interval [CI] .12–.27). Intervention characteristics that improve the effect size to a moderate level were intracurricular PA (SMD .43, 95% CI .19–.68), involving school staff in an intracurricular intervention (SMD .37, 95% CI .16–.58) and a tailored intracurricular intervention (SMD .35, 95% CI .13–.58). Meta-regression analysis confirmed PA as a positive predictor.ConclusionsThe effect of a school-based PA intervention was small to moderate. A sensible choice in the assembly of a multicomponent school-based PA intervention increases the effectiveness considerably. Physical education teachers, school administrators, and policy makers should consider organizational (intracurriculum, short and medium duration), personal (tailoring, participation), social (school staff) and content (PA) determinants.

Background Approximately 5%-10% of elementary school children show delayed development of fine motor skills. To address these problems, detection is required. Current assessment tools are time-consuming, require a trained supervisor, and are not motivating for children. Sensor-augmented toys and machine learning have been presented as possible solutions to address this problem. Objective This study examines whether sensor-augmented toys can be used to assess children’s fine motor skills. The objectives were to (1) predict the outcome of the fine motor skill part of the Movement Assessment Battery for Children Second Edition (fine MABC-2) and (2) study the influence of the classification model, game, type of data, and level of difficulty of the game on the prediction. Methods Children in elementary school (n=95, age 7.8 [SD 0.7] years) performed the fine MABC-2 and played 2 games with a sensor-augmented toy called “Futuro Cube.” The game “roadrunner” focused on speed while the game “maze” focused on precision. Each game had several levels of difficulty. While playing, both sensor and game data were collected. Four supervised machine learning classifiers were trained with these data to predict the fine MABC-2 outcome: k-nearest neighbor (KNN), logistic regression (LR), decision tree (DT), and support vector machine (SVM). First, we compared the performances of the games and classifiers. Subsequently, we compared the levels of difficulty and types of data for the classifier and game that performed best on accuracy and F1 score. For all statistical tests, we used α=.05. Results The highest achieved mean accuracy (0.76) was achieved with the DT classifier that was trained on both sensor and game data obtained from playing the easiest and the hardest level of the roadrunner game. Significant differences in performance were found in the accuracy scores between data obtained from the roadrunner and maze games (DT, P=.03; KNN, P=.01; LR, P=.02; SVM, P=.04). No significant differences in performance were found in the accuracy scores between the best performing classifier and the other 3 classifiers for both the roadrunner game (DT vs KNN, P=.42; DT vs LR, P=.35; DT vs SVM, P=.08) and the maze game (DT vs KNN, P=.15; DT vs LR, P=.62; DT vs SVM, P=.26). The accuracy of only the best performing level of difficulty (combination of the easiest and hardest level) achieved with the DT classifier trained with sensor and game data obtained from the roadrunner game was significantly better than the combination of the easiest and middle level (P=.046). Conclusions The results of our study show that sensor-augmented toys can efficiently predict the fine MABC-2 scores for children in elementary school. Selecting the game type (focusing on speed or precision) and data type (sensor or game data) is more important for determining the performance than selecting the machine learning classifier or level of difficulty.

De laatste jaren is er meer aandacht voor het dynamischer maken van de schooldag. Dagen waarop meer wordt bewogen en minder gezeten. In binnen- en buitenland zijn er meerdere beweegprogramma’s voor scholen ontwikkeld. Uit onderzoek blijkt dat de resultaten daarvan wisselend zijn. Wat opvalt is dat er - naast verschil in kwaliteit van het onderzoek - nauwelijks aandacht besteed wordt aan factoren die de implementatie van een beweegprogramma succesvol maken (Cassar e.a., 2019). In dit artikel gaan we in op de mogelijkheden en de complexiteit van het realiseren van een dynamische schooldag.

Kinderen brengen een groot deel van de schooldag zittend door. Meer bewegen in en om de school zou een manier kunnen zijn om de gezondheid van alle kinderen op school te bevorderen. Vaker een actieve pauze om kinderen gedurende de schooldag meer in beweging te laten zijn en minder te laten zitten, lijkt een simpele aanpassing van het dagprogramma op school. De vakleerkrachten bewegingsonderwijs van Stichting Westelijke Tuinsteden (STWT) in Amsterdam willen vormgeven aan een dynamische schooldag waarin kinderen regelmatig bewegen. Het lectoraat Bewegen in en om school (BIOS) van de Hogeschool van Amsterdam heeft als missie de vakleerkracht te ondersteunen in zijn rol als expert in en ambassadeur van bewegen op school. Dit artikel beschrijft welke stappen zij gezamenlijk zetten voor het behalen van succes in een veranderproces.

De laatste jaren is er steeds meer aandacht voor het meer dynamisch inrichten van de schooldag, maar wat is er bekend over het effect van beweegmomenten op school? In dit artikel vatten we recente literatuur samen op het gebied van de mogelijke effecten van beweegmomenten op school, zoals het lopen of fietsen van en naar school, bewegen tussen de lessen door (bewegingstussendoortjes), bewegen tijdens de les (bewegend leren), de buitenspeelpauze en het naschools sport- en beweegaanbod.

Welke rol heeft de kinderfysio- en kinderoefentherapeut bij de gezonde (motorische) ontwikkeling van kinderen in het primair onderwijs?

A regular short physical activity break in the classroom may improve classroom behavior. The current study reports on the results of the implementation of a daily 10-min Just Dance break in the classroom. A total of 31 Dutch primary school teachers agreed to participate in the study. We collected data on the frequency of the use of the Just Dance breaks via an online registration system. Data on the long-term barriers and facilitators of the implementation were collected using two online questionnaires. In addition, we held five interviews with teachers to elucidate data on barriers and facilitators. The results show that none of the teachers maintained the Just Dance breaks on a daily basis, and only 19% (n = 6) of the teachers on a weekly basis (i.e., one to three times a week). According to all participating teachers, a lack of time was the primary barrier to implement Just Dance breaks on a daily basis. Teachers who did not maintain Just Dance breaks on a weekly basis also experienced difficulties in 1) keeping all pupils engaged during the full 10-min Just Dance break or 2) getting the pupils focused again after the Just Dance break. Teachers who maintained the Just Dance breaks on a weekly basis provided several practical recommendations for a more sustainable implementation process. This study shows that the implementation process of daily Just Dance breaks is challenging. We recommend providing teachers with professional support when implementing physical activity breaks in their daily program.

In this study, we examined the effects of a defender contesting jump shots on performance and gaze behaviors of basketball players taking jump shots. Thirteen skilled youth basketball players performed 48 shots from about 5 m from the basket; 24 uncontested and 24 contested. The participants wore mobile eye tracking glasses to measure their gaze behavior. As expected, an approaching defender trying to contest the shot led to significant changes in movement execution and gaze behavior including shorter shot execution time, longer jump time, longer ball flight time, later final fixation onset, and longer fixation on the defender. Overall, no effects were found for shooting accuracy. However, the effects on shot accuracy were not similar for all participants: six participants showed worse performance and six participants showed better performance in the contested compared to the uncontested condition. These changes in performance were accompanied by differences in gaze behavior. The participants with worse performance showed shorter absolute and relative final fixation duration and a tendency for an earlier final fixation offset in the contested condition compared to the uncontested condition, whereas gaze behavior of the participants with better performance for contested shots was relatively unaffected. The results confirm that a defender contesting the shot is a relevant constraint for basketball shooting suggesting that representative training designs should also include contested shots, and more generally other constraints that are representative of the actual performance setting such as time or mental pressure.

Many studies have shown that self-controlled feedback is beneficial for learning motor tasks, and that learners prefer to receive feedback after supposedly good trials. However, to date all studies conducted on self-controlled learning have used individual tasks and mainly relatively simple skills. Therefore, the aim of this study was to examine self-controlled feedback on tactical skills in small-sided soccer games. Highly talented youth soccer players were assigned to a self-control or yoked group and received video feedback on their offensive performance in 3 vs. 2 small-sided games. The results showed that the self-control group requested feedback mostly after good trials, that is, after they scored a goal. In addition, the perceived performance of the self-control group was higher on feedback than on no-feedback trials. Analyses of the conversations around the video feedback revealed that the players and coach discussed good and poor elements of performance and how to improve it. Although the coach had a major role in these conversations, the players of the self-control group spoke more and showed more initiative compared to the yoked group. The results revealed no significant beneficial effect of self-controlled feedback on performance as judged by the coach. Overall, the findings suggest that in such a complex situation as small-sided soccer games, self-controlled feedback is used both to confirm correct performance elements and to determine and correct errors, and that self-controlled learning stimulates the involvement of the learner in the learning process.

In The Netherlands, the 4-Skills Scan is an instrument for physical education teachers to assess gross motor skills of elementary school children. Little is known about its reliability. Therefore, in this study the test–retest and inter-rater reliability was determined. Respectively, 624 and 557 Dutch 6- to 12-year-old children were analyzed for test re-test and inter-rater reliability. All tests took place within the school setting. The outcome measure was age-expected motor performance (in years). Results showed a small practice effect of .24 years for re-test sessions and assessment of motor skills was possible with acceptable precision (standard error of measurement = .67 years). Overall, intraclass correlation coefficient (ICC) was .93 (95% confidence interval: .92–.95) for test–retest reliability and .97 for inter-rater reliability. For the repeated measures, the smallest detectable change (SDC) was 1.84 and limits of agreement were –1.60 and 2.08 years. It can be concluded that the 4-Skills Scan is a reliable instrument to assess gross motor skills in elementary school children.

Muscle weakness and exercise intolerance negatively affect the quality of life of patients with mitochondrial myopathy. Short-term dietary nitrate supplementation has been shown to improve exercise performance and reduce oxygen cost of exercise in healthy humans and trained athletes. We investigated whether 1 wk of dietary inorganic nitrate supplementation decreases the oxygen cost of exercise and improves mitochondrial function in patients with mitochondrial myopathy. Ten patients with mitochondrial myopathy (40 ± 5 yr, maximal whole body oxygen uptake = 21.2 ± 3.2 ml·min−1·kg body wt−1, maximal work load = 122 ± 26 W) received 8.5 mg·kg body wt−1·day−1inorganic nitrate (~7 mmol) for 8 days. Whole body oxygen consumption at 50% of the maximal work load, in vivo skeletal muscle oxidative capacity (evaluated from postexercise phosphocreatine recovery using31P-magnetic resonance spectroscopy), and ex vivo mitochondrial oxidative capacity in permeabilized skinned muscle fibers (measured with high-resolution respirometry) were determined before and after nitrate supplementation. Despite a sixfold increase in plasma nitrate levels, nitrate supplementation did not affect whole body oxygen cost during submaximal exercise. Additionally, no beneficial effects of nitrate were found on in vivo or ex vivo muscle mitochondrial oxidative capacity. This is the first time that the therapeutic potential of dietary nitrate for patients with mitochondrial myopathy was evaluated. We conclude that 1 wk of dietary nitrate supplementation does not reduce oxygen cost of exercise or improve mitochondrial function in the group of patients tested.

Interventions to improve children&rsquo, s physical activity in Early Childhood Education and Care (ECEC) settings are needed. This randomized controlled trial examines the effects of a preschool-based playground program for ECEC teachers in a deprived urban area. On intervention preschools, the PLAYgrounds for TODdlers program (PLAYTOD) was performed. It focused on teacher&rsquo, s knowledge and skills in order to create a challenging outdoor environment in which young children (2.5 to 4 years old) are able to practice their motor skills. Observations were performed before and after the program with a modified version of the SOPLAY protocol. The activating role of teachers (score from 0 = inactive to 4 = participating), the number of different physical activities, and the quality of children&rsquo, s physical activity on playgrounds were observed. The latter included the number of performed fundamental movement skills and the estimated physical activity intensity (score from 0 = sedentary to 3 = vigorous). Descriptive statistics and linear regression analyses were used to evaluate the effects of PLAYTOD. After the program, the activating role of teachers on intervention playgrounds improved. Moreover, the program and consecutively the changes made by teachers had a positive effect on the number of different activities and the quality of children&rsquo, s physical activity. The results emphasize an important role for ECEC teachers in improving physical activity in young children.

and poster (poster title differs).

BackgroundInterventions to prevent overweight and obesity in toddlers are needed to minimize health inequalities, especially in migration and lower socio-economic groups. Preschools are identified as important environments for interventions to prevent overweight and obesity. Early Childhood Education and Care (ECEC) teachers in preschools are potential key actors in promoting healthy eating and physical activity. This paper describes the research design of a Dutch preschool-based intervention for ECEC teachers in promoting healthy eating and physical activity in toddlers.MethodsPreSchool@HealthyWeight concerns a cluster randomized controlled trial on preschools in Amsterdam Nieuw-West, Netherlands. This city district is characterised by inhabitants with a migration background and low socio-economic status. Forty-one preschools, with 115 ECEC teachers and 249 toddlers/parents, were randomly allocated to an intervention or control group. An intervention for teachers will be carried out on intervention locations and consists of modified versions of 2 existing programs: ‘A Healthy Start’ and ‘PLAYgrounds’. In ‘A Healthy Start’, ECEC teachers learn to provide a healthy and active environment for toddlers. The ‘PLAYgrounds for Toddlers’ program, coaches ECEC teachers to stimulate physical activity in the playgrounds of preschools. PreSchool@HealthyWeight aims to evaluate the effectiveness of the intervention after 9 months. Primary outcomes are the teachers’ knowledge, attitude and practices concerning healthy eating and physical activity, and consequently the level of confidence of ECEC teachers in promoting healthy eating and physical activity in toddlers. Secondary outcomes include the Body Mass Index, body composition, dietary intake and physical activity level of teachers and toddlers. In addition, the activating role of ECEC teachers and the physical activity of toddlers on the playgrounds will be evaluated. Lastly, the knowledge, attitude and practices of parents concerning healthy eating and physical activity will be assessed.DiscussionIt is hypothesized that this preschool-based intervention for ECEC teachers improves the knowledge, attitude and practices regarding healthy eating and physical activity, and consequently the level of confidence of ECEC teachers in promoting healthy eating and physical activity of toddlers. The intervention addresses the call for early intervention to prevent overweight and obesity and to minimize health inequalities.Trial registrationNetherlands Trial Register (NTR): NL5850. Date registered: August 26, 2016.

Made available in DSpace on 2019-10-04T12:33:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) This study tested whether adverse effects of state anxiety on attention and performance may be modulated by experience. Sixteen experienced and eleven inexperienced drivers drove in a simulator under low- and high-stress conditions. Anxiety was manipulated by competition, the presence of an evaluator, external video camera, and traffic noise. Most drivers showed greater anxiety scores and higher mean heart rates following manipulation. In both groups increased state anxiety decreased car speed control and caused more collisions, accompanied by fewer fixations of longer duration towards the driving lane across a horizontally narrower region. Inexperienced drivers increased the number of short fixations towards cars, while experienced drivers increased the number of short fixations on the speedometer. Although anxiety impairs processing efficiency and performance effectiveness for both groups, attentional changes differ as a function of experience. Inexperienced drivers tended to shift attention to threatening stimuli, while experienced drives were more likely to consciously monitor task goal. Univ Fed Sao Paulo, Paulista Sch Med, Hlth Informat Postgrad Program, Sao Paulo, SP, Brazil Sao Paulo State Univ, Fac Sci, Dept Phys Educ, Lab Informat Vis & Act, Bauru, SP, Brazil Sao Paulo State Univ, Fac Sci, Dept Phys Educ, Human Movement Sci Postgrad Program, Bauru, SP, Brazil Vrije Univ Amsterdam, Dept Human Movement Sci, Amsterdam Movement Sci, Amsterdam, Netherlands Amsterdam Univ Appl Sci Amsterdam, Fac Sports & Nutr, Amsterdam, Netherlands Manchester Metropolitan Univ, Inst Biomed Res Human Movement & Hlth, Manchester, Lancs, England Univ Portsmouth, Fac Sci, Dept Sport & Exercise Sci, Portsmouth, Hants, England Sao Paulo State Univ, Fac Sci, Dept Phys Educ, Lab Informat Vis & Act, Bauru, SP, Brazil Sao Paulo State Univ, Fac Sci, Dept Phys Educ, Human Movement Sci Postgrad Program, Bauru, SP, Brazil FAPESP: 2015/10851-3 CNPq: 458916/2014-5

In this study we examined in situ decision-making skills and gaze behaviour of skilled female basketball players. Players participated as ball carriers in a specific 3 vs 3 pick-and-roll basketball play. Playing both on the right and left side of the court and facing three types of defensive play, they chose and performed one of four options: shoot, drive to the basket, pass to the screener or pass to the corner player. We concurrently measured gaze behaviour to examine the direct relationship between gaze and decision making. As one of the first studies examining decision making and gaze behaviour in situ, this study found support for the embodied choice framework as the results showed that handling the ball with the dominant or non-dominant hand influenced the decisions that were made. Gaze measures suggested that peripheral vision may serve a significant role in decision making in situ, whereas players mainly relied on central vision to execute an action. Furthermore, this study underlined the need for developing and using newer and more informative methods to analyse gaze.

Altered skeletal muscle lipid metabolism is a hallmark feature of type 2 diabetes (T2D). We investigated muscle lipid turnover in T2D versus BMI-matched control subjects (controls) and examined whether putative in vivo differences would be preserved in the myotubes. Male obese T2D individuals (n = 6) and BMI-matched controls (n = 6) underwent a hyperinsulinemic-euglycemic clamp, VO2max test, dual-energy X-ray absorptiometry scan, underwater weighing, and muscle biopsy of the vastus lateralis. 14C-palmitate and 14C-oleate oxidation rates and incorporation into lipids were measured in muscle tissue as well as in primary myotubes. Palmitate oxidation (controls: 0.99 ± 0.17 nmol/mg protein; T2D: 0.53 ± 0.07 nmol/mg protein; P = 0.03) and incorporation of fatty acids (FAs) into triacylglycerol (TAG) (controls: 0.45 ± 0.13 nmol/mg protein; T2D: 0.11 ± 0.02 nmol/mg protein; P = 0.047) were significantly reduced in muscle homogenates of T2D. These reductions were not retained for palmitate oxidation in primary myotubes (P = 0.38); however, incorporation of FAs into TAG was lower in T2D (P = 0.03 for oleate and P = 0.11 for palmitate), with a strong correlation of TAG incorporation between muscle tissue and primary myotubes (r = 0.848, P = 0.008). The data indicate that the ability to incorporate FAs into TAG is an intrinsic feature of human muscle cells that is reduced in individuals with T2D.

Tendon pathology is related to metabolic disease and mechanical overloading, but the effect of metabolic disease on tendon mechanics is unknown. This study investigated the effect of diet and apolipoprotein E deficiency (ApoE−/−) on mechanical properties and advanced glycation end product (AGE) cross-linking of non-weight-bearing mouse tail tendons. Twenty ApoE−/− male mice were used as a model for hypercholesterolemia along with 26 wild-type (WT) mice. One-half of the mice from each group was fed a normal diet (ND) and the other half was fed a high-fat diet (HFD) to induce obesity. All were killed at 40 wk, and tail tendon fascicles were mechanically tested to failure and analyzed for AGEs. Diets were also analyzed for AGEs. ApoE−/− mice displayed a 14% increase in plateau modulus compared with WT mice ( P < 0.05), whereas HFD mice displayed a 13% decrease in plateau modulus ( P < 0.05) and a 12% decrease in total modulus ( P < 0.05) compared with ND mice. Tail tendons of HFD mice had significantly lower concentrations of AGEs [carboxymethyllysine (CML): 26%, P < 0.0001; methylglyoxal-derived hydroimidazolone 1 (MG-H1): 15%, P < 0.005; pentosidine: 13%, P < 0.0005]. The HFD had ∼44-fold lower content of CML ( P < 0.01), ∼29-fold lower content of carboxyethyllysine ( P < 0.005), and ∼16-fold lower content of MG-H1 ( P < 0.05) compared with ND. ApoE−/− increased, whereas HFD decreased mouse tail tendon stiffness. Dietary AGE content may be a crucial determinant for accumulation of AGE cross-links in tendons and for tissue compliance. The results demonstrate how systemic metabolic factors may influence tendon health.

Dynamic imbalance caused by external perturbations to gait can successfully be counteracted by adequate recovery responses. The current study investigated how the recovery response is moderated by age, walking speed, muscle strength and speed of information processing. The gait pattern of 50 young and 45 elderly subjects was repeatedly perturbed at 20% and 80% of the first half of the swing phase using the Timed Rapid impact Perturbation (TRiP) set-up. Recovery responses were identified using 2D cameras. Muscular factors (dynamometer) and speed of information processing parameters (computer-based reaction time task) were determined. The stronger, faster reacting and faster walking young subjects recovered more often by an elevating strategy than elderly subjects. Twenty three per cent of the differences in recovery responses were explained by a combination of walking speed (B=-13.85), reaction time (B=-0.82), maximum extension strength (B=0.01) and rate of extension moment development (B=0.19). The recovery response that subjects employed when gait was perturbed by the TRiP set-up was modified by several factors; the individual contribution of walking speed, muscle strength and speed of information processing was small. Insight into remaining modifying factors is needed to assist and optimise fall prevention programmes.

ImportanceEvidence for an acute effect of physical activity on cognitive performance within the school setting is limited. The purpose of this study was to gain insight into acute effects of a short physical activity bout on selective attention in primary school children, specifically in the school setting.MethodsHundred and twenty three 10–11 years old children, 49.6% girls, engaged in four experimental breaks in random order: 1 h of regular cognitive school tasks followed by a 15 min episode with the following conditions 1) ‘no break’ (continuing a cognitive task), 2) passive break (listening to a story), 3) moderate intensity physical activity break (jogging, passing, dribbling) and 4) vigorous intensity physical activity break (running, jumping, skipping). Selective attention in the classroom was assessed by the TEA-Ch test before and after the 15 min break in each condition.ResultsAfter the passive break, the moderate intensity physical activity break and the vigorous intensity physical activity break attention scores were significantly better (p ConclusionThe results show a significant positive effect of both a passive break as well as a physical activity break on selective attention, with the largest effect of a moderate intensity physical activity break. This suggests that schools could implement a moderate intensity physical activity break during the school day to optimize attention levels and thereby improve school performance.Trial registrationNTR2386.

This paper describes experiments with a game device that was used for early detection of delays in motor skill development in primary school children. Children play a game by bi-manual manipulation of the device which continuously collects ac- celerometer data and game state data. Features of the data are used to discriminate between normal children and children with delays. This study focused on the feature selection. Three features were compared: mean squared jerk (time domain); power spectral entropy (fourier domain) and cosine similarity measure (quality of game play). The discriminatory power of the features was tested in an experiment where 28 children played games of different levels of difficulty. The results show that jerk and cosine similarity have reasonable discriminatory power to detect fine-grained motor skill development delays especially when taking the game level into account. Duration of a game level needs to be at least 30 seconds in order to achieve good classification results.

Kinderen moeten de ruimte krijgen om de omgeving te ontdekken en hun motoriek en zintuigen te ontwikkelen. Het ontdekken van de omgeving gebeurt door bewegen, voelen, zien, ruiken, horen en proeven. En gaat dus gepaard met het ontwikkelen van de motoriek en de zintuigen. Stimuleren van beweging is van belang voor een geode motorische en zintuigelijke ontwikkeling.

Gymdocenten in het PO willen naast hun ´Gymmermansoog´ ook graag een objectieve beoordeling kunnen geven over de beweegvaardigheid van hun leerlingen. Hierdoor wordt de 4-vaardighedenscan veel gebruikt. In dit project wordt deze scan gevalideerd.

Objective—To determine the influence of intensified training and subsequent reduced training on glucose metabolism rate and peripheral insulin sensitivity in horses and identify potential markers indicative of early overtraining. Animals—12 Standardbred geldings. Procedures—Horses underwent 4 phases of treadmill-based training. In phase 1, horses were habituated to the treadmill. In phase 2, endurance training was alternated with high-intensity exercise training. In phase 3, horses were divided into control and intensified training groups. In the intensified training group, training intensity, duration, and frequency were further increased via a protocol to induce overtraining; in the control group, these factors remained unaltered. In phase 4, training intensity was reduced. Standardized exercise tests were performed after each phase and hyperinsulinemic euglycemic clamp (HEC) tests were performed after phases 2, 3, and 4. Results—10 of 12 horses completed the study. Dissociation between mean glucose metabolism rate and mean glucose metabolism rate-to-plasma insulin concentration ratio (M:I) was evident in the intensified training group during steady state of HEC testing after phases 3 and 4. After phase 4, mean glucose metabolism rate was significantly decreased (from 31.1 ± 6.8 μmol/kg/min to 18.1 ± 3.4 μmol/kg/min), as was M:I (from 1.05 ± 0.31 to 0.62 ± 0.17) during steady state in the intensified training group, compared with phase 3 values for the same horses. Conclusions and Clinical Relevance—Dissociation between the glucose metabolism rate and M:I in horses that underwent intensified training may reflect non-insulin–dependent increases in glucose metabolism.

Context: Conflicting data exist on mitochondrial function and physical activity in type 2 diabetes mellitus (T2DM) development. Objective: The aim was to assess mitochondrial function at different stages during T2DM development in combination with physical exercise in longstanding T2DM patients. Design and Methods: We performed cross-sectional analysis of skeletal muscle from 12 prediabetic 11 longstanding T2DM male subjects and 12 male controls matched by age and body mass index. Intervention: One-year intrasubject controlled supervised exercise training intervention was done in longstanding T2DM patients. Main Outcome Measurements: Extensive ex vivo analyses of mitochondrial quality, quantity, and function were collected and combined with global gene expression analysis and in vivo ATP production capacity after 1 yr of training. Results: Mitochondrial density, complex I activity, and the expression of Krebs cycle and oxidative phosphorylation system-related genes were lower in longstanding T2DM subjects but not in prediabetic subjects compared with controls. This indicated a reduced capacity to generate ATP in longstanding T2DM patients only. Gene expression analysis in prediabetic subjects suggested a switch from carbohydrate toward lipid as an energy source. One year of exercise training raised in vivo skeletal muscle ATP production capacity by 21 +/- 2% with an increased trend in mitochondrial density and complex I activity. In addition, expression levels of beta-oxidation, Krebs cycle, and oxidative phosphorylation system-related genes were higher after exercise training. Conclusions: Mitochondrial dysfunction is apparent only in inactive longstanding T2DM patients, which suggests that mitochondrial function and insulin resistance do not depend on each other. Prolonged exercise training can, at least partly, reverse the mitochondrial impairments associated with the longstanding diabetic state. (J Clin Endocrinol Metab 97: 3261-3269, 2012)

Lack of physical activity has been related to an increased risk of developing insulin resistance. This study aimed to assess the impact of chronic muscle deconditioning on whole body insulin sensitivity, muscle oxidative capacity, and intramyocellular lipid (IMCL) content in subjects with paraplegia. Nine subjects with paraplegia and nine able-bodied, lean controls were recruited. An oral glucose tolerance test was performed to assess whole body insulin sensitivity. IMCL content was determined both in vivo and in vitro using1H-magnetic resonance spectroscopy and fluorescence microscopy, respectively. Muscle biopsy samples were stained for succinate dehydrogenase (SDH) activity to measure muscle fiber oxidative capacity. Subcellular distributions of IMCL and SDH activity were determined by defining subsarcolemmal and intermyofibrillar areas on histological samples. SDH activity was 57 ± 14% lower in muscle fibers derived from subjects with paraplegia when compared with controls ( P < 0.05), but IMCL content and whole body insulin sensitivity did not differ between groups. In muscle fibers taken from controls, both SDH activity and IMCL content were higher in the subsarcolemmal region than in the intermyofibrillar area. This typical subcellular SDH and IMCL distribution pattern was lost in muscle fibers collected from subjects with paraplegia and had changed toward a more uniform distribution. In conclusion, the lower metabolic demand in deconditioned muscle of subjects with paraplegia results in a significant decline in muscle fiber oxidative capacity and is accompanied by changes in the subcellular distribution patterns of SDH activity and IMCL. However, loss of muscle activity due to paraplegia is not associated with substantial lipid accumulation in skeletal muscle tissue.

This study investigates the impact of protein coingestion with carbohydrate on muscle protein synthesis during endurance type exercise. Twelve healthy male cyclists were studied during 2 h of fasted rest followed by 2 h of continuous cycling at 55% Wmax. During exercise, subjects received either 1.0 g·kg−1·h−1 carbohydrate (CHO) or 0.8 g·kg−1·h−1 carbohydrate with 0.2 g·kg−1·h−1 protein hydrolysate (CHO+PRO). Continuous intravenous infusions with l-[ ring-13C6]phenylalanine and l-[ ring-2H2]tyrosine were applied, and blood and muscle biopsies were collected to assess whole body protein turnover and muscle protein synthesis rates at rest and during exercise conditions. Protein coingestion stimulated whole body protein synthesis and oxidation rates during exercise by 22 ± 3 and 70 ± 17%, respectively ( P < 0.01). Whole body protein breakdown rates did not differ between experiments. As a consequence, whole body net protein balance was slightly negative in CHO and positive in the CHO+PRO treatment (−4.9 ± 0.3 vs. 8.0 ± 0.3 μmol Phe·kg−1·h−1, respectively, P < 0.01). Mixed muscle protein fractional synthetic rates (FSR) were higher during exercise compared with resting conditions (0.058 ± 0.006 vs. 0.035 ± 0.006%/h in CHO and 0.070 ± 0.011 vs. 0.038 ± 0.005%/h in the CHO+PRO treatment, respectively, P < 0.05). FSR during exercise did not differ between experiments ( P = 0.46). We conclude that muscle protein synthesis is stimulated during continuous endurance type exercise activities when carbohydrate with or without protein is ingested. Protein coingestion does not further increase muscle protein synthesis rates during continuous endurance type exercise.

Hypothesis/objectives: Defining normal Growth Hormone (GH) secretory dynamics in the horse is necessary to understand altered GH dynamics related to issues like welfare and disease. Animals and methods: Twelve healthy yearlings and two mature Standardbreds were used to quantify GH secretion. Endogenous GH half-life was determined after administration of 1.0 microg/kg BW GH releasing hormone (GHRH). Exogenous GH half-life was determined after administration of 20 microg/kg BW recombinant equine GH (reGH) with and without suppression of endogenous GH secretion by somatostatin infusion (50 microg/m(2)/h). Pulse detection algorithm (Cluster) as well as deconvolution analysis was used to quantify GH secretory dynamics based on GH concentration-time series sampled every 5 min from 22:00 till 06:00 h. In addition, reproducibility, impact of sampling frequency and influence of altering initial GH half-life on parameter estimates were studied. Results: Mean endogenous GH half-life of 17.7 +/- 4.4 (SD) min and mean exogenous half-life of 26.0 +/- 2.9 min were found. The mean number of GH secretion peaks in 8 h was 12 +/- 3.2. Ninety-nine percent of the total amount of GH secreted occurred in pulses, basal secretion was 0.012 +/- 0.014 microg/L/min and half-life was 8.9 +/- 2.6 min. Compared with a 5-min sampling frequency, 20- and 30-min sampling underestimated the number of secretory events by 45% and 100%, respectively. Conclusions: The deconvolution model used was valid to GH time series in Standardbreds. As in man, the equine pituitary gland secretes GH in volleys consisting of multiple secretory bursts, without measurable intervening tonic secretion. The required GH sampling frequency for the horse should be around 3 min. Clinical relevance: Defining normal GH secretory dynamics in the horse will make it possible to detect alterations in the GH axis due to pathophysiologic mechanisms as well as abuse of reGH.

The aim of the present study was to examine whether pretreatment with different fatty acids, as well as the liver X receptor (LXR) agonist T0901317, could modify metabolic switching of human myotubes. The n-3 FA eicosapentaenoic acid (EPA) increased suppressibility, the ability of glucose to suppress FA oxidation. Substrate-regulated flexibility, the ability to increase FA oxidation when changing from a high glucose, low fatty acid condition ("fed") to a high fatty acid, low glucose ("fasted") condition, was increased by EPA and other n-3 FAs. Adaptability, the capacity to increase FA oxidation with increasing FA availability, was enhanced after pretreatment with EPA, linoleic acid (LA), and palmitic acid (PA). T0901317 counteracted the effect of EPA on suppressibility and adaptability, but it did not affect these parameters alone. EPA per se accumulated less, however, EPA, LA, oleic acid, and T0901317 treatment increased the number of lipid droplets (LD) in myotubes. LD volume and intensity, as well as mitochondrial mass, were independent of FA pretreatment. Microarray analysis showed that EPA regulated more genes than the other FAs and that specific pathways involved in carbohydrate metabolism were induced only by EPA. The present study suggests a favorable effect of n-3 FAs on skeletal muscle metabolic switching and glucose utilization.

The major aim of the present study was to investigate the proteome of standardbred horses at different stages of training and intensified training. We searched for biomarkers using small skeletal muscle biopsies of live animals. 2D gel electrophoresis and mass spectrometry were successfully applied to investigate training-induced differential expression of equine muscle biopsy proteins. Despite the poor resolution of the equine genome and proteome, we were able to identify the proteins of 20 differential spots representing 16 different proteins. Evaluation of those proteins complies with adaptation of the skeletal muscle after normal training involving structural changes towards a higher oxidative capacity, an increased capacity to take up long-chain fatty acids, and to store energy in the form of glycogen. Intensified training leads to additional changed spots. Alpha-1-antitrypsin was found increased after intensified training but not after normal training. This protein may thus be considered as a marker for overtraining in horses and also linked to overtraining in human athletes.

International audience; The present study examined differences in visual search and locomotor behaviours among a group of skilled 10-12 year old football players. The participants watched video clips of a 4-to-4 position game, presented on a large screen. The participants were asked to take part in the game by choosing the best position for the reception of the ball passed by one of the players in the clip. Participants' visual search and locomotor behaviours were collected continuously throughout the presentation of the clip. A within-group comparison was made based upon the participants' interception score, i.e. more at the correct position. The findings show that the high-score group looked more to the ball area, while the players in the low-score group concentrated on the receiving player and on the hips/upper body region of the passing player. The players in the high score group covered a significant greater distance compared to the low score group. It is concluded that the within-group comparison revealed differences in visual search and locomotion behaviour that can be used as indicators for identifying talented junior football players.

OBJECTIVE Mitochondrial dysfunction and fat accumulation in skeletal muscle (increased intramyocellular lipid [IMCL]) have been linked to development of type 2 diabetes. We examined whether exercise training could restore mitochondrial function and insulin sensitivity in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS Eighteen male type 2 diabetic and 20 healthy male control subjects of comparable body weight, BMI, age, and Vo2max participated in a 12-week combined progressive training program (three times per week and 45 min per session). In vivo mitochondrial function (assessed via magnetic resonance spectroscopy), insulin sensitivity (clamp), metabolic flexibility (indirect calorimetry), and IMCL content (histochemically) were measured before and after training. RESULTS Mitochondrial function was lower in type 2 diabetic compared with control subjects (P = 0.03), improved by training in control subjects (28% increase; P = 0.02), and restored to control values in type 2 diabetic subjects (48% increase; P < 0.01). Insulin sensitivity tended to improve in control subjects (delta Rd 8% increase; P = 0.08) and improved significantly in type 2 diabetic subjects (delta Rd 63% increase; P < 0.01). Suppression of insulin-stimulated endogenous glucose production improved in both groups (−64%; P < 0.01 in control subjects and −52% in diabetic subjects; P < 0.01). After training, metabolic flexibility in type 2 diabetic subjects was restored (delta respiratory exchange ratio 63% increase; P = 0.01) but was unchanged in control subjects (delta respiratory exchange ratio 7% increase; P = 0.22). Starting with comparable pretraining IMCL levels, training tended to increase IMCL content in type 2 diabetic subjects (27% increase; P = 0.10), especially in type 2 muscle fibers. CONCLUSIONS Exercise training restored in vivo mitochondrial function in type 2 diabetic subjects. Insulin-mediated glucose disposal and metabolic flexibility improved in type 2 diabetic subjects in the face of near–significantly increased IMCL content. This indicates that increased capacity to store IMCL and restoration of improved mitochondrial function contribute to improved muscle insulin sensitivity.

International audience; Oral or intravenous administration of labeled, free amino acids does not allow the direct assessment of protein digestion and absorption kinetics following dietary protein intake. Consequently, dietary protein sources with labeled amino acids incorporated within the protein are required. The aim of this study was to produce milk proteins intrinsically labeled with l-[1-13C]phenylalanine that would allow the assessment of protein digestion and absorption kinetics and the subsequent muscle protein synthetic response to dietary protein intake in vivo in humans. Two Holstein cows (body weight of 726 ± 38 kg) were continuously infused with l-[1-13C]phenylalanine at 402 μmol/min for 44 to 48 h, during and after which plasma samples and milk were collected. After milk protein separation, casein was used in a subsequent human proof-of-principle experiment. Two healthy males (aged 61 ± 1 yr; body mass index of 22.4 ± 0.1 kg/m2) ingested 35 g of casein highly enriched with [1-13C] phenylalanine. Plasma samples were collected at regular intervals, and skeletal muscle biopsies were collected before and 6 h after casein ingestion. In the initial experiment, a total of 5.83 kg of l-[1-13C]phenylalanine–enriched milk protein (casein enrichment was 29.4 molar percent excess) was collected during stable isotope infusion in the cows. In the proof-of-principle study, ingestion of 35 g of intrinsically labeled casein resulted in peak plasma l-[1-13C] phenylalanine enrichments within 90 min after protein ingestion (9.75 ± 1.47 molar percent excess). Skeletal muscle protein synthesis rates calculated over the entire 6-h period averaged 0.058 ± 0.012%/h. The production of intrinsically labeled milk protein is feasible and provides dietary protein that can be used to investigate protein digestion and absorption and the subsequent muscle protein synthetic response in vivo in humans. Key words: milk synthesis , dietary protein , digestion and absorption , muscle protein synthesis

We determined muscle fiber type-specific hypertrophy and changes in satellite cell (SC) content following a 12-week resistance training program in 13 healthy, elderly men (72 +/- 2 years). Leg strength and body composition (dual-energy X-ray absorptiometry and computed tomography) were assessed, and muscle biopsy samples were collected. Leg strength increased 25%-30% after training (p < .001). Leg lean mass and quadriceps cross-sectional area increased 6%-9% (p < .001). At baseline, mean fiber area and SC content were smaller in the Type II versus Type I muscle fibers (p < .01). Following training, Type II muscle fiber area increased from 5,438 +/- 319 to 6,982 +/- 503 mum(2) (p < .01). Type II muscle fiber SC content increased from 0.048 +/- 0.003 to 0.084 +/- 0.008 SCs per fiber (p < .001). No changes were observed in the Type I muscle fibers. In older adults, skeletal muscle tissue is still capable of inducing SC proliferation and differentiation, resulting in Type II muscle fiber hypertrophy.

Recently, we identified several flavonoids as inhibitors of the nuclear enzyme poly(ADP-ribose) polymerase (PARP)-1 in vitro and in vivo. PARP-1 is recognized as coactivator of nuclear factor-kappaB and plays a role in the pathophysiology of diseases with low-grade systemic inflammation, such as chronic obstructive pulmonary disease (COPD) and type 2 diabetes (T2D). In this study, we assessed the antiinflammatory effects of flavonoids with varying PARP-1-inhibiting effects in whole blood from male patients with COPD or T2D and healthy men. A total of 10 COPD, 10 T2D patients, and 10 healthy volunteers matched for age and BMI were recruited. Blood from each participant was exposed to 1 microg/L lipopolysaccharide (LPS) over 16 h with or without preincubation with 10 micromol/L of flavone, fisetin, morin, or tricetin. Concentrations of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, -8, and -10 were measured in the supernatant. Preincubation with fisetin and tricetin strongly attenuated LPS-induced increases in concentrations of TNFalpha in blood from COPD patients [mean (+/- SEM): -41 +/- 4% (fisetin) and -31 +/- 4% (tricetin); P < 0.001] and IL-6 in blood from T2D patients [-31 +/- 5% (fisetin) and -29 +/- 6% (tricetin); P < or = 0.001]. Moreover, LPS-induced changes in TNFalpha and IL-6 concentrations were positively correlated with the extent of reduction by fisetin and tricetin. The PARP-1-inhibiting flavonoids fisetin and tricetin were able to attenuate LPS-induced cytokine release from leukocytes of patients with chronic systemic inflammation, indicating a potential application as nutraceutical agents for these patient groups.

The capacity to perform physical activity largely depends on physical fitness. Muscle fiber-type distribution (Muscle(FTD)) is associated with physical fitness and may influence the capacity to perform physical activity. The purpose of this study was to determine whether habitual physical activity in daily life (PA(DL)) and Muscle(FTD) are related. Thirty-eight healthy non-athletes (31 women, 7 men) were recruited. PA(DL) was measured twice for 14 days using a tri-axial accelerometer for movement registration (Tracmor). From Tracmor output, the proportion of time subjects were physically active at low, moderate, and high intensities was determined (%Low, %Moderate, and %High, respectively). A total activity index (PA(index)) and sub-scores on work, leisure-time and sports were obtained using the Baecke questionnaire. Muscle(FTD) was determined using immuno-fluorescence against respective myosin heavy chain isoforms. No relationship was observed between PA(DL) and Muscle(FTD). %Low, %Moderate, and %High, as well as PA(index) and its sub-scores, were not related to Muscle(FTD) either. The time spent on sports was associated with the proportion of type I and II(X) fibers (P=0.06 and P